Semiconductor device and manufacturing method thereof

ABSTRACT

A semiconductor device includes a first semiconductor chip comprising a first metallic structure, a top surface, and a bottom surface, a second semiconductor chip comprising a second metallic structure, wherein the second semiconductor chip is bonded with the first semiconductor chip on the bottom surface, a conductive material connecting the first metallic structure and the second metallic structure, wherein a portion of the conductive material is inside the first semiconductor chip and the second semiconductor chip, and a dielectric layer disposed surrounding the portion of the conductive material.

BACKGROUND

Electronic equipment using semiconductor devices are essential for manymodern applications. With the advancement of electronic technology,electronic equipment is becoming increasingly smaller in size whilehaving greater functionality and greater amounts of integratedcircuitry. Thus, semiconductor devices inside the electronic equipmentare also becoming denser, smaller and more compact. The continuousdemands for a size reduction of semiconductor devices has made itnecessary to develop more integrated circuits that can be accommodatedwithin the semiconductor devices.

The major trend in the electronic industry is to make the semiconductordevices smaller and more multifunctional. Thus, a semiconductor devicecomprises an electrical interconnection structure for electricallyconnecting a number of metallic structures between adjacent layers ofthe semiconductor device so as to minimize the final size of thesemiconductor device as well as the electronic equipment. The electricalinterconnection structure includes a number of trenches or vias whichare filled with a conductive material, such as copper or aluminum, andare pierced through several adjacent layers in the semiconductor devicein order to connect circuits between adjacent layers.

However, manufacturing of the electrical interconnection structure iscomplicated because it involves numerous manufacturing operations andthose operations are applied on the semiconductor device, which includesmany different kinds of materials with different properties. Thedifferences between the materials would increase the complexity ofmanufacturing the semiconductor devices and may cause deficiencies. Suchdeficiencies may include poor bondability between layers, poorreliability of the trenches, and cracking or delamination of theelectrical interconnection structure. As such, there is a continuousneed to improve the method for manufacturing the electricalinterconnection structure so as to solve the above deficiencies.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isemphasized that, in accordance with the standard practice in theindustry, various features are not drawn to scale. In fact, thedimensions of the various features may be arbitrarily increased orreduced for clarity of discussion.

FIG. 1 is a schematic view of a semiconductor device including a firstsemiconductor chip and a second semiconductor chip in accordance withsome embodiments of the present disclosure.

FIG. 1A is a schematic view of a first insulating layer inside a firstsemiconductor chip in accordance with some embodiments of the presentdisclosure.

FIG. 2 is a schematic view of a semiconductor device including a firstrecessed portion and a second recessed portion in a steppedconfiguration in accordance with some embodiments of the presentdisclosure.

FIG. 2A is a schematic view a semiconductor device including a firstsemiconductor chip, a second semiconductor chip and a metal plug inaccordance with some embodiments of the present disclosure.

FIG. 3 is a flow diagram of a method of manufacturing a semiconductordevice in accordance with some embodiments of the present disclosure.

FIG. 3A is a schematic view of provision of a first semiconductor chipin accordance with some embodiments of the present disclosure.

FIG. 3B is a schematic view of provision of a second semiconductor chipin accordance with some embodiments of the present disclosure.

FIG. 3C is a schematic view of bonding a first semiconductor chip with asecond semiconductor chip in accordance with some embodiments of thepresent disclosure.

FIG. 3D is a schematic view of forming a first recessed portion inaccordance with some embodiments of the present disclosure.

FIG. 3E is a schematic view of forming a second recessed portion inaccordance with some embodiments of the present disclosure.

FIG. 3F is a schematic view of forming a dielectric layer in accordancewith some embodiments of the present disclosure.

FIG. 3G is a schematic view of removing a portion of a dielectric layerin accordance with some embodiments of the present disclosure.

FIG. 3H is a schematic view of forming a conductive material inaccordance with some embodiments of the present disclosure.

FIG. 4 is a flow diagram of a method of manufacturing a semiconductordevice in accordance with some embodiments of the present disclosure.

FIG. 4A is a schematic view of provision of a first semiconductor chipin accordance with some embodiments of the present disclosure.

FIG. 4B is a schematic view of provision of a second semiconductor chipin accordance with some embodiments of the present disclosure.

FIG. 4C is a schematic view of bonding a first semiconductor chip with asecond semiconductor chip in accordance with some embodiments of thepresent disclosure.

FIG. 4D is a schematic view of forming a first recessed portion inaccordance with some embodiments of the present disclosure.

FIG. 4E is a schematic view of forming a second recessed portion inaccordance with some embodiments of the present disclosure.

FIG. 4F is a schematic view of forming a dielectric layer in accordancewith some embodiments of the present disclosure.

FIG. 4G is a schematic view of removing a portion of a dielectric layerin accordance with some embodiments of the present disclosure.

FIG. 4H is a schematic view of forming a conductive material inaccordance with some embodiments of the present disclosure.

DETAILED DESCRIPTION OF THE DISCLOSURE

A semiconductor device is manufactured by a number of operations. Duringthe manufacturing, an electrical interconnection structure is formedbetween a number of conductive metallic structures across a number ofinsulating layers of at least two semiconductor chips in thesemiconductor device. The conductive metallic structures are connectedwith each other by piercing a number of trenches or vias from asemiconductor chip to another semiconductor chip. The trench is formedby etching through the semiconductor chips. The trench is then coated orfilled with a conductive material, so that the conductive metallicstructures are electrically connected across the semiconductor chipsthrough the trench coated or filled with the conductive material.

However, the insulating layers of a semiconductor chip include variouskinds of materials such as silicon oxide, black diamond (Black Diamond®(Applied Materials of Santa Clara, Calif.)) and silicon carbide etc.which have different etch rates to a predetermined etchant. As such, alateral etching of sidewall of the trench is suffered. The lateraletching leads to an uneven and rough sidewall surface and thus induces apoor reliability upon disposition of the conductive material on thesidewall of the trench.

The manufacturing and use of the embodiments of the present disclosureare discussed in details below. It should be appreciated, however, thatthe embodiments provide many applicable inventive concepts that can beembodied in a wide variety of specific contexts. It is to be understoodthat the following disclosure provides many different embodiments orexamples for implementing different features of various embodiments.Specific examples of components and arrangements are described below tosimplify the present disclosure. These are, of course, merely examplesand are not intended to be limiting.

Embodiments, or examples, illustrated in the drawings are disclosedbelow using specific language. It will nevertheless be understood thatthe embodiments and examples are not intended to be limiting. Anyalterations and modifications in the disclosed embodiments, and anyfurther applications of the principles disclosed in this document arecontemplated as would normally occur to one of ordinary skill in thepertinent art.

Further, it is understood that several processing steps and/or featuresof a device may be only briefly described. Also, additional processingsteps and/or features can be added, and certain of the followingprocessing steps and/or features can be removed or changed while stillimplementing the claims. Thus, the following description should beunderstood to represent examples only, and are not intended to suggestthat one or more steps or features is required.

In addition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

In the present disclosure, a semiconductor device with an improvedelectrical interconnection structure is disclosed. The electricalinterconnection structure includes a recessed portion which is coatedwith an oxide layer in order to improve a smoothness of a sidewallsurface of the recessed portion and thus prevent the poor reliability ofthe electrical interconnection structure and yield loss of thesemiconductor device.

FIG. 1 is a diagram of a semiconductor device 100 in accordance withvarious embodiments of the present disclosure. The semiconductor device100 includes a first semiconductor chip 101-1. The first semiconductorchip 101-1 includes a first substrate 101 g, a first insulating layer103-1 and a first metallic structure 102 a-1 disposed within the firstinsulating layer 103-1.

In some embodiments, the first semiconductor chip 101-1 is asemiconductor sensor chip. In some embodiments, the first semiconductorchip 101-1 is fabricated by a complementary metal-oxide-semiconductor(CMOS) process techniques known in the art to become a CMOS image sensor(CIS) chip. The CIS chip is widely used in a digital camera application.The CIS chip is configured for capturing a light and converting thelight into an electrical signal.

In some embodiments, the first semiconductor chip 101-1 comprises anepitaxial (EPI) layer (not shown) over a silicon substrate, and thesilicon substrate is removed during a backside thinning operation untilthe EPI layer is exposed. In some embodiments, a portion of the EPI isremained. In some embodiments, a p-type photo active region and ann-type photo active region (not shown respectively) are formed in theremaining epitaxial layer.

In some embodiments, the first semiconductor chip 101-1 includes atransistor (not shown) which generates a signal related to an intensityor a brightness of a light projected on the photo active regions. Insome embodiments, the transistor may be a transfer transistor. However,the transistor may be an example of the many types of functionaltransistors utilized within the first semiconductor chip 101-1. In someembodiments, the transistor may include other transistors such as areset transistor, a source follower transistor or a select transistor.All suitable transistors and configurations utilized in the firstsemiconductor chip 101-1 are fully intended to be included within thescope of the embodiments.

In some embodiments, the first substrate 101 g of the firstsemiconductor chip 101-1 includes silicon, germanium, gallium, arsenic,and combinations thereof. In some embodiments, the first substrate 101 gis in a form of silicon-on-insulator (SOI) including a layer of asemiconductor material (e.g., silicon, germanium and/or the like) formedover an insulator layer (e.g., buried oxide and/or the like). In someembodiments, the first substrate 101 g includes multi-layeredsubstrates, gradient substrates, hybrid orientation substrates, anycombinations thereof and/or the like.

In some embodiments, the first substrate 101 g comprises a variety ofelectrical circuits (not shown) formed on the first substrate 102. Insome embodiments, the electrical circuits is any one type of circuitriessuitable for a particular application. In some embodiments, theelectrical circuits includes various n-type metal-oxide semiconductor(NMOS) and/or p-type metal-oxide semiconductor (PMOS) devices such astransistors, capacitors, resistors, diodes, photo-diodes, fuses and/orthe like. In some embodiments, the electrical circuits may beinterconnected to perform one or more functions including memorystructures, processing structures, sensors, amplifiers, powerdistribution, input/output circuitry and/or the like. One of ordinaryskill in the art will appreciate that the above examples are providedfor illustrative purposes only and are not intended to limit the variousembodiments to any particular applications.

In some embodiments, the first insulating layer 103-1 is an inter-metaldielectric (IMD) layer including a dielectric material for isolating anumber of conductive metallic structures from each other inside thefirst insulating layer 103-1. In some embodiments, the first insulatinglayer 103-1 includes at least two adjacent layers differing in etchrates to a predetermined etchant. In some embodiments, the at least twoadjacent layers have difference in materials with different etch ratesaround 700 nm/min to a predetermined etchant CF4 gas. The layers areremoved in different rates under the predetermined etchant upon theetching operation. In some embodiments, the at least two adjacent layersinclude a silicon oxide layer, silicon carbide layer and a black diamond(Black Diamond® (Applied Materials of Santa Clara, Calif.) layer, whichhave different etch rates from each other.

In some embodiments, the first metallic structure 102 a-1 of the firstsemiconductor chip 101-1 is disposed within the first insulating layer103-1. The first insulating layer 103-1 encapsulates the first metallicstructure 102 a-1. In some embodiments, the first metallic structure 102a-1 includes gold, silver, copper, nickel, tungsten, aluminum, palladiumand/or alloys thereof. In some embodiments, the first metallic structure102 a-1 is a portion of a first metal interconnection of the firstsemiconductor chip 101-1.

In some embodiments, the semiconductor device 100 includes a secondsemiconductor chip 101-2. In some embodiments, the first semiconductorchip 101-1 is bonded with the second semiconductor chip 101-2. In someembodiments, the first semiconductor chip 101-1 and the secondsemiconductor chip 101-2 are bonded together through any suitablebonding techniques such as direct bonding. In some embodiments, thefirst semiconductor chip 101-1 is bonded by an interface 101 f betweenthe first semiconductor chip 101-1 and the second semiconductor chip101-2. In some embodiments, the first semiconductor chip 101-1 and thesecond semiconductor chip 101-2 are bonded together by a metal-to-metalbonding (e.g., copper-to-copper bonding), dielectric-to-dielectricbonding (e.g., oxide-to-oxide bonding), metal-to-dielectric bonding(e.g., oxide-to-copper bonding), any combinations thereof and/or thelike.

In some embodiments, the interface 101 f is between a passivation layer101 d of the first semiconductor chip 101-1 and a passivation layer 101e of the second semiconductor chip 101-2. In some embodiments, thepassivation layer 101 d and the passivation layer 101 e are respectivelyan oxide layer including silicon oxide. In some embodiments, thepassivation layer 101 d and the passivation layer 101 e respectivelyincludes silicon nitride. In some embodiments, the passivation layer 101d and the passivation layer 101 e respectively includes a compositestructure, hybrid bond, bonding interface including metal such ascopper, and dielectric such as silicon oxide or silicon nitride.

In some embodiments, the second semiconductor chip 101-2 is asemiconductor application specific integrated circuit (ASIC) chip whichis configured for a particular application. In some embodiments, thesecond semiconductor chip 101-2 includes several logic circuits such asan analog-to-digital converter, a data processing circuit, a memorycircuit, a bias circuit, a reference circuit, any combinations thereofand/or the like.

In some embodiments, the second semiconductor chip 101-2 includes asecond substrate 101 h, a second insulating layer 103-2 and a secondmetallic structure 102 a-2. In some embodiments, the second substrate101 h includes silicon, germanium, gallium, arsenic, and combinationsthereof. In some embodiments, the second substrate 101 h is in a form ofsilicon-on-insulator (SOI). In some embodiments, the second substrate101 h is multi-layered substrates, gradient substrates, hybridorientation substrates, any combinations thereof and/or the like.

In some embodiments, the second substrate 101 h includes a variety ofelectrical circuits (not shown). The electrical circuits formed on thesecond substrate 101 h are configured for a particular application. Insome embodiments, the electrical circuits may be interconnected toperform one or more functions such as memory structures, processingstructures, sensors, amplifiers, power distribution, input/outputcircuitry and/or the like. One of ordinary skill in the art willappreciate that the above examples are provided for illustrativepurposes only and are not intended to limit the various embodiments toany particular applications.

In some embodiments, the second insulating layer 103-2 is an inter-metaldielectric (IMD) layer including a dielectric material for isolating anumber of conductive metallic structures from each other inside thesecond insulating layer 103-2. In some embodiments, the secondinsulating layer 103-2 includes various dielectric materials commonlyused in integrated circuit fabrication. In some embodiments, the secondinsulating layer 103-2 includes silicon dioxide, silicon nitride or adoped glass layer such as boron silicate glass and the like. In someembodiments, the second insulating layer 103-2 is formed using suitabletechniques such as sputtering, oxidation, CVD and/or the like.

In some embodiments, the second metallic structure 102 a-2 of the secondsemiconductor chip 101-2 is disposed within the second insulating layer103-2. The second insulating layer 103-2 encapsulates the secondmetallic structure 102 a-2. In some embodiments, the second metallicstructure 102 a-2 includes gold, silver, copper, nickel, tungsten,aluminum, palladium and/or alloys thereof. In some embodiments, thesecond metallic structure 102 a-2 is a portion of a first metalinterconnection of the second semiconductor chip 101-2.

In some embodiments, the first semiconductor chip 101-1 includes a topsurface 101 a. The top surface 101 a includes a first recessed portion106-1 and a second recessed portion 106-2. In some embodiments, thefirst recessed portion 106-1 includes a first sidewall 103 d-1 along thefirst recessed portion 106-1. In some embodiments, the top surface 101 aincludes a first recessed portion 106-1 extended from the top surface101 a to the first metallic structure 102 a-1. In some embodiments, thefirst recessed portion 106-1 is extended from the top surface 101 a to aportion 102 b-1 of the first metallic structure 102 a-1 disposed on orwithin the first metallic structure 102 a-1. In some embodiments, theportion 102 b-1 of the first metallic structure 102 a-1 is coplanar witha bottom surface of the first recessed portion 106-1. In someembodiments, the first recessed portion 106-1 is configured in acylindrical shape with a circular cross-section.

In some embodiments, the first metallic structure 102 a-1 includessuitable metallic materials such as copper, which is of a differentetching rate (selectivity) from the first substrate 101 g and the firstinsulating layer 103-1. As such, the first metallic structure 102 a-1 isfunctioned as a hard mask layer for an etching operation of the firstinsulating layer 103-1. In some embodiments, a selective etchingoperation is employed to etch the first insulating layer 103-1 rapidly,while a portion 102 b-1 of the first metallic structure 102 a-1 ispartially etched away, thereby forming the first recessed portion 106-1and forming the bottom surface of the first recessed portion 106-1 on orwithin the first metallic structure 102 a-1. The depth of the firstrecessed portion 106-1 varies depending on different applications anddesign needs.

In some embodiments, the first recessed portion 106-1 includes a depthD_(first recess) from the top surface 101 a of the first semiconductorchip 101 to the portion 102 b-1 of the first metallic structure 102 a-1.In some embodiments, the depth D_(first recess) of the first recessedportion 106-1 is about 1 um to about 5 um.

In some embodiments, the first recessed portion 106-1 includes a widthW_(first recess) between the first sidewall 103 d-1. In someembodiments, the width W_(first recess) of the first recessed portion106-1 is about 5 um to about 12 um.

In some embodiments, the second recessed portion 106-2 is extended fromthe top surface 101 a towards the second metallic structure 102 a-2. Insome embodiments, the second recessed portion 106-2 passes through thefirst semiconductor chip 101-1 and the second semiconductor chip 101-2.In some embodiments, the second recessed portion 106-2 includes a secondsidewall 103 d-2 surrounded by the at least two adjacent layers of thefirst insulting layer 103-1 with different materials. In someembodiments, the portion 102 b-2 of the second metallic structure 102a-2 is coplanar with a bottom surface of the second recessed portion106-2. In some embodiments, the second recessed portion 106-2 isconfigured in a cylindrical shape with a circular cross-section.

In some embodiments, the second metallic structure 102 a-2 includessuitable metallic materials such as copper, which is of a differentetching rate (selectivity) from the second substrate 101 h and thesecond insulating layer 103-2. As such, the second metallic structure102 a-2 is functioned as a hard mask layer for an etching operation ofthe second insulating layer 103-2. In some embodiments, a selectiveetching operation is employed to etch the second insulating layer 103-2rapidly, while a portion 102 b-2 of the second metallic structure 102a-2 is partially etched away, thereby forming the second recessedportion 106-2 and forming the bottom surface of the second recessedportion 106-2 on or within the second metallic structure 102 a-2. Thedepth of the second recessed portion 106-2 varies depending on differentapplications and design needs.

In some embodiments, the second recessed portion 106-2 includes a depthD_(second recess) from the top surface 101 a of the first semiconductorchip 101 to the portion 102 b-2 of the second metallic structure 102a-2. In some embodiments, the depth D_(second recess) of the secondrecessed portion 106-2 is about 6 um to about 12 um.

In some embodiments, the second recessed portion 106-2 includes a widthW_(second recess) between the second sidewall 103 d-2. In someembodiments, the width W_(second recess) of the second recessed portion106-2 is about 5 um to about 12 um.

In some embodiments, the second recessed portion 106-2 includes a numberof staggered portions 103 e on a second sidewall 103 d-2 of the secondrecessed portion 106-2 surrounded by the first insulating layer 103-1.As the first insulating layer 103-1 includes various kinds of materialswith different etch rates, the number of staggered portions 103 e aredisposed on the second sidewall 103 d-2 along the second recessedportion 106-2.

FIG. 1A is an enlarged view of an embodiment of the staggered portions103 e of the second recessed portion 106-2 in accordance with variousembodiments of the present disclosure. In some embodiments, thestaggered portions 103 e are surrounded by the first insulating layer103-1 of the first semiconductor chip 101-1. In some embodiments, thefirst insulating layer 103-1 includes a silicon carbide layer 103 a anda black diamond layer 103 b which are spaced in an interval. In someembodiments, the second recessed portion 106-2 is formed by etching someof the silicon carbide layer 103 a and some of the black diamond layer103 b. The etch rate of the black diamond layer 103 b is faster than theetch rate of the silicon carbide layer 103 a 700 nm/min to apredetermined etchant CF4.

As the difference in the etch rates of the silicon carbide layer 103 aand the black diamond layer 103 b, the second sidewall 103 d-2 of thefirst insulating layer 103-1 includes the number of staggered portions103 e along the second sidewall 103 d-2 of the second recessed portion106-2. In some embodiments, the black diamond layer 103 b is recessedlaterally relative to the silicon carbide layer 103 a with a depth whichis a length l_(staggered) as shown in FIG. 1A. In some embodiments, thestaggered portions 103 e surrounded by the black diamond layer 103 b islaterally indented towards an exterior 103 f of the first insulatinglayer 103-1. The staggered portion 103 e surrounded by the siliconcarbide layer 103 a is laterally protruded towards the second recessedportion 106-2. In some embodiments, the silicon carbide layer 103 aprotruded from the black diamond layer 103 b is in the lengthl_(staggered) about 46 nm to about 76 nm. In some embodiments, thelength l_(staggered) is about 40 nm to about 80 nm.

Referring back to FIG. 1, in some embodiments, a dielectric layer 104 isdisposed on the top surface 101 a of the first semiconductor chip 101-1,the first sidewall 103 d-1 of the first recessed portion 106-1 and thesecond sidewall 103 d-2 of the second recessed portion 106-2. In someembodiments, some portions of the dielectric layer 104 are disposedwithin the staggered portions 103 e. In some embodiments, the portion102 b-1 of the first metallic structure 102 a-1 and the portion 102 b-2of the second metallic structure 102 a-2 are not covered by thedielectric layer 104. In some embodiments, the dielectric layer 104 isan oxide layer which includes a plasma enhanced oxide (PEOX). In someembodiments, the dielectric layer 104 includes a non-conductive materialsuch as silicon dioxide. In some embodiments, the dielectric layer 104is formed using suitable techniques such as sputtering, oxidation oretc.

In some embodiments, a conductive material 105 covers the dielectriclayer 104, the portion 102 b-1 of the first metallic structure 102 a-1in the first semiconductor chip 101-1 and the portion 102 b-2 of thesecond metallic structure 102 a-2 in the second semiconductor chip101-2. In some embodiments, the first metallic structure 102 a-1 of thefirst semiconductor chip 101-1 is configured for electrically connectingwith the second metallic structure 102 a-2 in the second semiconductorchip 101-2. As such, the first metallic structure 102 a-1 iselectrically connected with the second metallic structure 102 a-2 alongthe conductive material 105. In some embodiments, the conductivematerial 105 is coated on the dielectric layer 104, the portion 102 b-1of the first metallic structure 102 a-1 and the portion 102 b-2 of thesecond metallic structure 102 a-2 by electroplating or sputtering oretc. The conductive material 105 is a metallic coating including gold,silver, copper, nickel, tungsten, aluminum, palladium and/or alloysthereof. In some embodiments, a thickness T_(conductive) of theconductive material 105 is about 4 kA to 12 kA. In some embodiments, thethickness

FIG. 2 is a diagram of a semiconductor device 100 in accordance withvarious embodiments of the present disclosure. In some embodiments, thesemiconductor device 100 includes a first semiconductor chip 101-1 and asecond semiconductor chip 101-2. The first semiconductor chip 101-1includes a top surface 101 a, a first insulating layer 103-1 and a firstmetallic structure 102 a-1. The second semiconductor chip 101-2 includesa second insulating layer 103-2 and a second metallic structure 102 a-2.

In some embodiments, the first semiconductor chip 101-1 is a CMOS imagesensor chip, and the second semiconductor chip 101-2 is an ASIC chip.The first semiconductor chip 101-1 is bonded with the secondsemiconductor chip 101-2 by the interface 101 f between the firstsemiconductor chip 101-1 and the second semiconductor chip 101-2. Insome embodiments, the first semiconductor chip 101-1 includes the firstmetallic structure 102 a-1 for electrically connecting with the secondmetallic structure 102 a-2 in the second semiconductor chip 101-2. Thefirst semiconductor chip 101-1 includes the first insulating layer 103-1including at least two adjacent layers differing in etch rates to apredetermined etchant.

In some embodiments, the first semiconductor chip 101-1 includes a topsurface 101 a. The top surface 101 a includes a first recessed portion106-1. The first recessed portion 106-1 extends from the top surface 101a to a portion 102 b-1 of the first metallic structure 102 a-1. In someembodiments, the first recessed portion 106-1 includes a first sidewall103 d-1 along the first recessed portion 106-1 and a bottom surfacedisposed on or within the first metallic structure 102 a-1.

In some embodiments, the first metallic structure 102 a-1 includessuitable metallic materials such as copper, which is of a differentetching rate (selectivity) from the first substrate 101 g and the firstinsulating layer 103-1. As such, the first metallic structure 102 a-1 isfunctioned as a hard mask layer for an etching operation of the firstinsulating layer 103-1. In some embodiments, a selective etchingoperation is employed to etch the first insulating layer 103-1 rapidly,while a portion 102 b-1 of the first metallic structure 102 a-1 ispartially etched away, thereby forming the first recessed portion 106-1with a first sidewall 103 d-1. The depth of the first recessed portion106-1 varies depending on different applications and design needs.

In some embodiments, a second recessed portion 106-2 extends from theportion 102 b-1 of the first metallic structure 102 a-1 to a portion 102b-2 of the second metallic structure. In some embodiments, the secondrecessed portion 106-2 includes a second sidewall 103 d-2 along thesecond recessed portion 106-2 and a bottom surface disposed on or withinthe second metallic structure 102 a-2. The second recessed portion 106-2passes through the first semiconductor chip 101-1 and the secondsemiconductor chip 101-2.

In some embodiments, the second metallic structure 102 a-2 includessuitable metallic materials such as copper, which is of a differentetching rate (selectivity) from the second substrate 101 h and thesecond insulating layer 103-2. As such, the second metallic structure102 a-2 is functioned as a hard mask layer for an etching operation ofthe second insulating layer 103-2. In some embodiments, a selectiveetching operation is employed to etch the second insulating layer 103-2rapidly, while a portion 102 b-2 of the second metallic structure 102a-2 is partially etched away, thereby forming the second recessedportion 106-2 with a second sidewall 103 d-2 and forming the bottomsurface of the second recessed portion 106-2 on or within the secondmetallic structure 102 a-2. The depth of the second recessed portion106-2 varies depending on different applications and design needs.

In some embodiments, the first recessed portion 106-1 and the secondrecessed portion 106-2 are in a stepped configuration. The firstsidewall 103 d-1 and the second sidewall 103 d-2 are in a number ofsteps from the top surface 101 a of the first semiconductor chip 101-1towards the second metallic structure 102 a-2. In some embodiments, afirst width w_(recess-1) of the first recessed portion 106-1 is largerthan a second width w_(recess-2) of the second recessed portion 106-2.

In some embodiments, the first sidewall 103 d-1 surrounded by the firstinsulating layer 103-1 of the first semiconductor chip 101-1 includes anumber of staggered portions 103 e. As the first insulating layer 103-1includes various kinds of materials with different etch rates, thenumber of staggered portions 103 e are disposed on the first sidewall103 d-1 along the first recessed portion 106-1 surrounded by the firstinsulating layer 103-1.

In some embodiments, the top surface 101 a of the first semiconductorchip 101-1, the first sidewall 103 d-1 of the first recessed portion106-1 and the second sidewall 103 d-2 of the second recessed portion106-2 are covered by a dielectric layer 104. In some embodiments, theportion 102 b-1 of the first metallic structure 102 a-1 and the portion102 b-2 of the second metallic structure 102 a-2 are not covered by thedielectric layer 104. In some embodiments, some portions of thedielectric layer 104 are disposed within the number of staggeredportions 103 e. In some embodiments, the dielectric layer 104 is anon-conductive coating which is in a stepped configuration compliancewith a profile of the first recessed portion 106-1 and the secondrecessed portion 106-2.

In some embodiments, the dielectric layer 104, the portion 102 b-1 ofthe first metallic structure 102 a-1 in the first semiconductor chip101-1 and the portion 102 b-2 of the second metallic structure 102 a-2in the second semiconductor chip 101-2 are covered by a conductivematerial 105, so that the first metallic structure 102 a-1 iselectrically connected with the second metallic structure 102 a-2. Insome embodiments, the conductive material 105 is a metal coating whichis in a stepped configuration conformal over the dielectric layer 104,the portion 102 b-1 and the portion 102 b-2.

In some embodiments, the conductive material 105 is a metal plugdisposing and filling the first recessed portion 106-1 and the secondrecessed portion 106-2 in a stepped configuration as in FIG. 2A. In someembodiments, the metal plug is disposed on the dielectric layer 104, theportion 102 b-1 of the first metallic structure 102 a-1 and the portion102 b-2 of the second metallic structure 102 a-2 by electroplating. Insome embodiments, the metal plug includes gold, silver, copper, nickel,tungsten, aluminum, palladium and/or alloys thereof.

In the present disclosure, a method of manufacturing a semiconductordevice is also disclosed. In some embodiments, a semiconductor device isformed by a method 200 or a method 300. The method 200 or the method 300includes a number of operations and the description and illustration arenot deemed as a limitation as the sequence of the operations.

FIG. 3 is a flowchart of a method 200 of manufacturing a semiconductordevice. The method 200 includes a number of operations (201, 202, 203,204, 205, 206, 207 and 208).

In operation 201, a first semiconductor chip 101-1 is provided as inFIG. 3A. The first semiconductor chip 101-1 includes a first metallicstructure 102 a-1 inside the first semiconductor chip 101-1 and a topsurface 101 a. In some embodiments, the first semiconductor chip 101-1includes a first insulating layer 103-1 including a various kinds ofmaterials with different etch rates such as silicon carbide, blackdiamond, etc.

In some embodiments, the first semiconductor chip 101-1 includes apassivation layer 101 d which is disposed opposite to the top surface101 a of the first semiconductor chip 101-1. In some embodiments, thefirst semiconductor chip 101-1 is fabricated by a complementarymetal-oxide-semiconductor (CMOS) process techniques known in the art tobecome a CMOS image sensor (CIS) chip.

In operation 202, a second semiconductor chip 101-2 is provided as inFIG. 3B. In some embodiments, the second semiconductor chip 101-2 is anASIC chip. In some embodiments, the second semiconductor chip 101-2includes a second metallic structure 102 a-2 inside the secondsemiconductor chip 101-2. The second semiconductor chip 101-2 includes asecond insulating layer 103-2 and a passivation layer 101 e. Thepassivation layer 101 e is adjacent to an interface 101 f for bondingwith the first semiconductor chip 101-1.

In operation 203, the first semiconductor chip 101-1 is bonded with thesecond semiconductor chip 101-2 as in FIG. 3C. In some embodiments, thefirst semiconductor chip 101-1 and the second semiconductor chip 101-2are bonded together through any suitable bonding techniques such asdirect bonding. In some embodiments, the first semiconductor chip 101-1and the second semiconductor chip 101-2 are bonded by the interface 101f between the passivation layer 101 d of the first semiconductor chip101-1 and the passivation layer 101 e of the second semiconductor chip101-2. In some embodiments, the first semiconductor chip 101-1 is bondedwith the second semiconductor chip 101-2 through a suitablemetal-dielectric bonding technique such as a copper-silicon oxidenitride (Cu—SiON) bonding process.

In operation 204, a first recessed portion 106-1 is formed as in FIG.3D. The first recessed portion 106-1 is formed from the top surface 101a of the first semiconductor chip 101-1 towards the first metallicstructure 102 a-1, so that a portion 102 b-1 of the first metallicstructure 102 a-1 is exposed. The first recessed portion 106-1 includesthe first sidewall 103 d-1 and a bottom surface coplanar with theportion 102 b-1 of the first metallic structure 102 a-1. The firstrecessed portion 106-1 is surrounded by the first insulating layer103-1. In some embodiments, the bottom surface of the first recessedportion 106-1 is disposed on or within the first metallic structure 102a-1.

In some embodiments, the first recessed portion 106-1 is formed byetching of the first insulating layer 103-1. The etching is an operationof selectively dissolving and removing one or more kinds of materials bya predetermined etchant such as CF4. Some of the first insulating layer103-1 are prevented from etching by a masking material such as aphotolithography patterned-photoresist to form the first recessedportion 106-1. The first recessed portion 106-1 is formed depending onhow long time of the etching operations and which types of etchants areused. In some embodiments, the etch rate of silicon dioxide is 3 um/min,that is a thickness of 3 um of the silicon dioxide is etched away everyminute. In some embodiments, the first recessed portion 106-1 is formedby suitable deposition and photolithography techniques such as areactive ion etch (RIE) or other dry etch, an anisotropic wet etch, anyother suitable anisotropic etching or etc.

In operation 205, a second recessed portion 106-2 is formed as in FIG.3E. In some embodiments, the second recessed portion 106-2 is formedfrom the top surface 101 a to a portion 102 b-2 of the second metallicstructure 102 a-2. The second recessed portion 106-2 passes from thefirst semiconductor chip 101-1 to the second semiconductor chip 101-2.In some embodiments, the second recessed portion 106-2 includes thesecond sidewall 103 d-2 and a bottom surface coplanar with the portion102 b-2 of the second metallic structure 102 a-2. In some embodiments,the bottom surface of the second recessed portion 106-2 is disposed onor within the second metallic structure 102 a-2. In some embodiments,the second recessed portion 106-2 is surrounded by the first insulatinglayer 103-1. The second recessed portion 106-2 is extended from the topsurface 101 a of the first semiconductor chip 101-1 towards the secondmetallic structure 102 a-2 of the second semiconductor chip 101-2, sothat the portion 102 b-2 of the second metallic structure 102 a-2 isexposed.

In some embodiments, the second recessed portion 106-2 is formed byetching of the first insulating layer 103-1. Upon the etchingoperations, a number of staggered portions 103 e are formed on thesecond sidewall 103 d-2 of the second recessed portion 106-2 surroundedby the first insulating layer 103-1, because the first insulating layer103-1 includes various kinds of materials with different etch rates to apredetermined etchant. As such, the sidewall 103 d-1 is in an uneven andrough surface along the second recessed portion 106-2 towards the secondmetallic structure 102 a-2.

In operation 206, a dielectric layer 104 is formed as in FIG. 3F. Insome embodiments, the dielectric layer 104 is coated on the top surface101 a of the first semiconductor chip 101-1, the first sidewall 103 d-1of the first recessed portion 106-1, the second sidewall 103 d-2 of thesecond recessed portion 106-2, the portion 102 b-1 of the first metallicstructure 102 a-1 and the portion 102 b-2 of the second metallicstructure 102 a-2. In some embodiments, the dielectric layer 104 is acoating including non-conductive material such as silicon dioxide. Insome embodiments, the dielectric layer 104 covers and fills thestaggered portions 103 e in order to smoothen the rough surface of thesecond sidewall 103 d-2 of the second recessed portion 106-2.

In operation 207, some portions of the dielectric layer 104 on theportion 102 b-1 of the first metallic structure 101-1 and the portion102 b-2 of the second metallic structure 101-2 are removed as in FIG.3G. As some portions of the dielectric layer 104 are not covered by thepatterned photoresist, those uncovered portions of the dielectric layer104 are dissolved and removed by etching by a predetermined etchant, andthus the portion 102 b-1 of the first metallic structure 102 a-1 and theportion 102 b-2 of the second metallic structure 102 a-2 are thenexposed.

In operation 208, a conductive material 105 is formed on the dielectriclayer 104, the portion 102 b-1 of the first metallic structure 102 a-1and the portion 102 b-2 of the second metallic structure 102 a-2 as inFIG. 3H. In some embodiments, the conductive material 105 is formed byelectroplating or sputtering. The first metallic structure 102 a-1 isthen electrically connected with the second metallic structure 102 a-2via the conductive material 105 passing from the top surface 101 a, thefirst recessed portion 106-1 to the second recessed portion 106-2. Insome embodiments, the conductive material 105 includes gold, silver,copper, nickel, tungsten, aluminum, palladium and/or alloys thereof.

FIG. 4 is an embodiment of a method 300 of manufacturing a semiconductordevice. The method 300 includes a number of operations (301, 302, 303,304, 305, 306, 307 and 308). In some embodiments, operations 201-203 inFIG. 3A-3C are similar to operations 301-303 in FIG. 4A-4C.

In operation 304, a first recessed portion 106-1 is formed as in FIG.4D. The first recessed portion 106-1 is formed from the top surface 101a of the first semiconductor chip 101-1 towards the first metallicstructure 102 a-1, so that a portion 102 b-1 of the first metallicstructure 102 a-1 is exposed. In some embodiments, the first recessedportion 106-1 includes the first sidewall 103 d-1 and a bottom surfacecoplanar with the portion 102 b-1 of the first metallic structure 102a-1. In some embodiments, the bottom surface of the first recessedportion 106-1 is disposed on or within the first metallic structure 102a-1. In some embodiments, the first recessed portion 106-1 is surroundedby the first insulating layer 103-1.

In some embodiments, the first recessed portion 106-1 is formed byetching of the first insulating layer 103-1. The etching is an operationof selectively dissolving and removing one or more kinds of materials bya predetermined etchant. Some of the first insulating layer 103-1 areprevented from etching by a masking material such as a photolithographypatterned-photoresist to form the first recessed portion 106-1. Thefirst recessed portion 106-1 is formed depending on how long time of theetching operations and which types of etchants are used. In someembodiments, the first recessed portion 106-1 is formed by suitabledeposition and photolithography techniques such as a reactive ion etch(RIE) or other dry etch, an anisotropic wet etch, any other suitableanisotropic etching or etc.

In some embodiments, a number of staggered portions 103 e are formed onthe first sidewall 103 d-1 of the first recessed portion 106-1surrounded by the first insulating layer 103-1 upon the etchingoperations, because the first insulating layer 103-1 includes variouskinds of materials with different etch rates to a predetermined etchant.As such, the first sidewall 103 d-1 is in an uneven and rough surfacealong the first recessed portion 106-1.

In operation 305, a second recessed portion 106-2 is formed as in FIG.4E. In some embodiments, the second recessed portion 106-2 is formedfrom the portion 102 b-1 of the first metallic structure 102 a-1 to aportion 102 b-2 of the second metallic structure 102 a-2, so that theportion 102 b-2 is exposed. In some embodiments, the second recessedportion 106-2 is formed by etching of the first insulating layer 103-1and the second insulating layer 103-2. The second recessed portion 106-2passes from the first semiconductor chip 101-1 to the secondsemiconductor chip 101-2. The second recessed portion 106-2 is extendedfrom the bottom surface of the first recessed portion 106-1 towards thesecond metallic structure 102 a-2.

In some embodiments, the second recessed portion 106-2 includes thesecond sidewall 103 d-2 and a bottom surface coplanar with the portion102 b-2 of the second metallic structure 102 a-2. In some embodiments,the bottom surface of the second recessed portion 106-2 is disposed onor within the second metallic structure 102 a-2. In some embodiments,the first recessed portion 106-1 is coupled within the second recessedportion 106-2. In some embodiments, the first recessed portion 106-1 isdisposed above the second recessed portion 106-2. In some embodiments,the second recessed portion 106-2 is surrounded by the first insulatinglayer 103-1 and the second insulating layer 103-2.

In operation 306, a dielectric layer 104 is formed as in FIG. 4F. Insome embodiments, the dielectric layer 104 is coated on the top surface101 a of the first semiconductor chip 101-1, the first sidewall 103 d-1of the first recessed portion 106-1, the second sidewall 103 d-2 of thesecond recessed portion 106-1, the portion 102 b-1 of the first metallicstructure 102 a-1 and the portion 102 b-2 of the second metallicstructure 102 a-2. In some embodiments, the dielectric layer 104 is acoating including non-conductive material such as silicon dioxide. Insome embodiments, the dielectric layer 104 covers and fills thestaggered portions 103 e in order to smoothen the rough surface of thefirst sidewall 103 d-1 of the first recessed portion 106-1.

In operation 307, some portions of the dielectric layer 104 on theportion 102 b-1 of the first metallic structure 101-1 and the portion102 b-2 of the second metallic structure 101-2 are removed as in FIG.4G. In some embodiments, some portions of the dielectric layer 104 aredissolved and removed by etching, so that the portion 102 b-1 of thefirst metallic structure 102 a-1 and the portion 102 b-2 of the secondmetallic structure 102 a-2 are then exposed.

In operation 308, a conductive material 105 is formed on the dielectriclayer 104, the portion 102 b-1 of the first metallic structure 102 a-1and the portion 102 b-2 of the second metallic structure 102 a-2 as inFIG. 4H. In some embodiments, the conductive material 105 is formed byelectroplating or sputtering. The first metallic structure 102 a-1 isthen electrically connected with the second metallic structure 102 a-2via the conductive material 105 passing from the top surface 101 a, thefirst recessed portion 106-1 to the second recessed portion 106-2. Insome embodiments, the conductive material 105 includes gold, silver,copper, nickel, tungsten, aluminum, palladium and/or alloys thereof.

In some embodiments, a semiconductor device includes a firstsemiconductor chip comprising a first metallic structure, a firstsurface, a second surface opposite to the first surface, and a firstinsulating layer including at least two adjacent layers differing inetch rate to a predetermined etchant; a second semiconductor chipcomprising a second metallic structure and bonded with the firstsemiconductor chip on the second surface; a first recessed portionextended from the first surface of the first semiconductor chip to thefirst metallic structure, wherein the first recessed portion includes afirst sidewall and a bottom surface disposed on or within the firstmetallic structure; a second recessed portion extended to the secondmetallic structure, wherein the second recessed portion includes asecond sidewall and a bottom surface disposed on or within the secondmetallic structure; a dielectric layer disposed on the first sidewall ofthe first recessed portion and the second sidewall of the secondrecessed portion; and a conductive material disposed on the firstsurface, the dielectric layer, a portion of the first metallic structureinterfaced with the bottom surface of the first recessed portion and aportion of the second metallic structure interfaced with the bottomsurface of the second recessed portion, the first metallic structurebeing electrically connected with the second metallic structure.

In some embodiments, the at least two adjacent layers surround a portionof the first sidewall or a portion of the second sidewall. In someembodiments, the second recessed portion is extended from the firstsurface or from the first metallic structure. In some embodiments, thefirst recessed portion is coupled with the second recessed portion. Insome embodiments, the first recessed portion is disposed above thesecond recessed portion. In some embodiments, the first sidewall or thesecond sidewall includes a staggered portion covered by the dielectriclayer. In some embodiments, one of the at least two adjacent layers isrecessed laterally relative to another with a depth. In someembodiments, the at least two adjacent layers include silicon carbideand black diamond. In some embodiments, a thickness of the conductivematerial is about 4 kA to 12 kA. In some embodiments, the conductivematerial includes gold, silver, copper, nickel, tungsten, aluminum,palladium and/or alloys thereof. In some embodiments, the first recessedportion and the second recessed portion are in a stepped configuration.

In some embodiments, a semiconductor device includes a firstsemiconductor chip comprising a first metallic structure, a top surface,and a bottom surface; a second semiconductor chip comprising a secondmetallic structure, wherein the second semiconductor chip is bonded withthe first semiconductor chip on the bottom surface; a conductivematerial connecting the first metallic structure and the second metallicstructure, wherein a portion of the conductive material is inside thefirst semiconductor chip and the second semiconductor chip; and adielectric layer surrounding the portion of the conductive material.

In some embodiments, the dielectric layer is disposed on a sidewall of afirst recessed portion extended from the top surface to the firstmetallic structure or a sidewall of a second recessed portion extendedfrom the top surface to the second metallic structure. In someembodiments, the first semiconductor chip is a semiconductor imagesensor chip and the second semiconductor chip is a semiconductor ASICchip. In some embodiments, the bottom surface interfaced with the firstsemiconductor chip and the second semiconductor chip is surrounded by apassivation.

In some embodiments, a method of manufacturing a semiconductor deviceincludes providing a first semiconductor chip comprising a firstmetallic structure and a first surface and a second surface opposite tothe first surface; providing a second semiconductor chip comprising asecond metallic structure; bonding the first semiconductor chip with thesecond semiconductor chip on the second surface; forming a firstrecessed portion including a first sidewall and a first bottom surfacecoplanar with a top surface of the first metallic structure; forming asecond recessed portion including a second sidewall and a second bottomsurface coplanar with a top surface of the second metallic structure;forming a dielectric layer on the first sidewall and the secondsidewall; and forming a conductive material on the dielectric layer, thetop surface of the first metallic structure and the top surface of thesecond metallic structure to electrically connect the first metallicstructure and the second metallic structure.

In some embodiments, the method further includes removing the dielectriclayer on the top surface of the first metallic structure and the topsurface of the second metallic structure by etching. In someembodiments, the first recessed portion or the second recessed portionis formed by etching. In some embodiments, the first recessed portionextends from the first surface, and the second recessed portion extendsfrom the first surface or the top surface of the first metallicstructure. In some embodiments, the dielectric layer disposed on thefirst sidewall is thicker than the dielectric layer disposed on thefirst metallic structure.

The methods and features of this disclosure have been sufficientlydescribed in the above examples and descriptions. It should beunderstood that any modifications or changes without departing from thespirit of the disclosure are intended to be covered in the protectionscope of the disclosure.

Moreover, the scope of the present application in not intended to belimited to the particular embodiments of the process, machine,manufacture, and composition of matter, means, methods and stepsdescribed in the specification. As those skilled in the art will readilyappreciate from the disclosure of the present disclosure, processes,machines, manufacture, composition of matter, means, methods or stepspresently existing or later to be developed, that perform substantiallythe same function or achieve substantially the same result as thecorresponding embodiments described herein maybe utilized according tothe present disclosure.

Accordingly, the appended claims are intended to include within theirscope such as processes, machines, manufacture, compositions of matter,means, methods or steps. In addition, each claim constitutes a separateembodiment, and the combination of various claims and embodiments arewithin the scope of the disclosure.

What is claimed is:
 1. A semiconductor device, comprising: a firstsemiconductor chip comprising a first metallic structure, a firstsurface, a second surface opposite to the first surface, and a firstinsulating layer including at least two adjacent layers differing inetch rate to a predetermined etchant; a second semiconductor chipcomprising a second metallic structure and bonded with the firstsemiconductor chip on the second surface; a first recessed portionextended from the first surface of the first semiconductor chip to thefirst metallic structure, wherein the first recessed portion includes afirst sidewall and a bottom surface disposed on or within the firstmetallic structure; a second recessed portion extended from the firstsurface to the second metallic structure, wherein the second recessedportion includes a second sidewall and a bottom surface disposed on orwithin the second metallic structure; a dielectric layer disposed on thefirst sidewall of the first recessed portion and the second sidewall ofthe second recessed portion; and a conductive material disposed DIRECTLYon the first surface, the dielectric layer, a portion of the firstmetallic structure interfaced with the bottom surface of the firstrecessed portion and a portion of the second metallic structureinterfaced with the bottom surface of the second recessed portion, thefirst metallic structure being electrically connected with the secondmetallic structure, wherein the first sidewall or the second sidewallincludes a staggered portion covered by the dielectric layer.
 2. Thesemiconductor device of claim 1, wherein the at least two adjacentlayers surround a portion of the first sidewall or a portion of thesecond sidewall.
 3. The semiconductor device of claim 1, wherein thesecond recessed portion is extended from the first surface or from thefirst metallic structure.
 4. The semiconductor device of claim 1,wherein the first recessed portion is coupled with the second recessedportion.
 5. The semiconductor device of claim 1, wherein the firstrecessed portion is disposed above the second recessed portion.
 6. Thesemiconductor device of claim 1, wherein one of the at least twoadjacent layers is recessed laterally relative to another with a depth.7. The semiconductor device of claim 1, wherein the at least twoadjacent layers include silicon carbide and black diamond.
 8. Thesemiconductor device of claim 1, wherein a thickness of the conductivematerial is about 4 kA to 12 kA.
 9. The semiconductor device of claim 1,wherein the conductive material includes gold, silver, copper, nickel,tungsten, aluminum, palladium and/or alloys thereof.
 10. Thesemiconductor of claim 1, wherein the first recessed portion and thesecond recessed portion are in a stepped configuration.
 11. Thesemiconductor device of claim 1, wherein the second recessed portionpasses through the first semiconductor chip and the second semiconductorchip.
 12. The semiconductor device of claim 1, wherein the dielectriclayer is disposed conformal to the first sidewall or the secondsidewall.
 13. The semiconductor device of claim 1, wherein thedielectric layer includes oxide.
 14. The semiconductor device of claim1, wherein the dielectric layer is disposed between the conductivematerial and the first insulating layer or the second insulating layer.15. The semiconductor device of claim 1, wherein a portion of thedielectric layer is disposed within the staggered portion.